TypeScript Array shift()

In this chapter, we will explore the shift() method for arrays in TypeScript. This method is a built-in function that removes the first element from an array and returns that element. This method changes the length of the array. Understanding how to use shift() is useful for managing and modifying arrays, especially when you need to remove elements from the beginning of the array.

Table of Contents

1. Definition
2. Syntax
3. Examples
4. Conclusion

1. Definition

The shift() method removes the first element from an array and returns that element. This method changes the length of the array.

2. Syntax

array.shift();

Parameters

The shift() method does not take any parameters.

Return Value

The method returns the removed element from the array. If the array is empty, it returns undefined.

3. Examples

Let's look at some examples to understand how shift() works in TypeScript.

Example 1: Basic Usage

In this example, we use shift() to remove the first element from an array of numbers.

let numbers: number[] = [1, 2, 3, 4, 5];
let firstElement = numbers.shift();
console.log(firstElement); // Output: 1
console.log(numbers);      // Output: [2, 3, 4, 5]

Example 2: Using shift() on a String Array

In this example, we use shift() to remove the first element from an array of strings.

let fruits: string[] = ["apple", "banana", "mango"];
let firstFruit = fruits.shift();
console.log(firstFruit); // Output: "apple"
console.log(fruits);     // Output: ["banana", "mango"]

Example 3: Using shift() on an Empty Array

In this example, we use shift() on an empty array to see how it behaves.

let emptyArray: number[] = [];
let result = emptyArray.shift();
console.log(result); // Output: undefined
console.log(emptyArray); // Output: []

Example 4: Removing Objects from an Array

In this example, we use shift() to remove the first object from an array of objects.

interface Person {
  name: string;
  age: number;
}

let people: Person[] = [
  { name: "Ravi", age: 25 },
  { name: "Ankit", age: 30 },
  { name: "Priya", age: 28 },
];

let firstPerson = people.shift();
console.log(firstPerson); // Output: { name: 'Ravi', age: 25 }
console.log(people);      // Output: [ { name: 'Ankit', age: 30 }, { name: 'Priya', age: 28 } ]

Example 5: Using shift() in a Loop

In this example, we use shift() in a loop to empty an array.

let numbers: number[] = [1, 2, 3, 4, 5];
while (numbers.length > 0) {
  console.log(numbers.shift());
}
// Output:
// 1
// 2
// 3
// 4
// 5

4. Conclusion

In this chapter, we explored the shift() method for arrays in TypeScript, which is used to remove the first element from an array and return that element. We covered its definition, syntax, parameters, return value, and provided several examples to demonstrate its usage. Understanding how to use shift() effectively can help in various array manipulation tasks in TypeScript, especially when managing and modifying arrays by removing elements from the beginning.